Method and apparatus for acquiring cell identifier in radio communication system

ABSTRACT

A method for acquiring a cell identifier by a source cell in a radio communication system is provided. The method includes receiving information about a new cell from a User Equipment (UE) in the source cell, acquiring an Evolved Universal Terrestrial Radio Access (EUTRA) Cell Global Identifier (ECGI) of the new cell from the UE, if it is determined based on the information about the new cell that there is no neighbor relationship with the new cell, determining whether a Public Land Mobile Network (PLMN) Identifier (ID) (PLMN ID) in the ECGI is included in a mapping table between a primary PLMN ID and a shared PLMN ID, and acquiring an X2 Internet Protocol (IP) address of the new cell from an Evolved Packet Core (EPC) according to the determination results.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. §119(a) of a Koreanpatent application filed on Mar. 20, 2013 in the Korean IntellectualProperty Office and assigned Serial number 10-2013-0029667, the entiredisclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a method and apparatus for acquiringcell identifiers in a radio communication system. More particularly, thepresent disclosure relates to a method and apparatus for acquiring cellidentifiers in an environment where multiple operators share cells.

BACKGROUND

When an enhanced Node B (eNB) is newly or additionally installed, theeNB executes a self-configuration process. Self-configuration is anautomated function for identifying a neighbor eNB, registeringrelationship setup, and setting up a connection to the core network inan eNB's initial boot-up process and a pre-operation phase. In otherwords, the self-configuration process is a method ofself-collecting/analyzing the parameters needed for an eNB's initialoperation.

In the self-configuration operation process, after an eNB is powered onand connected to a transport link, the eNB may perform self-detectionfunctions after the basic self-hardware verification. The self-detectionfunctions may include functions of detecting the transport type and thelength of an antenna cable, and automatically adjusting the path of areceiver. After performing the self-detection function, the eNB may setup a physical transfer link, and acquire information about its InternetProtocol (IP) address and an IP address to a relevant service or torelevant equipment such as a serving gateway, a Mobility ManagementEntity (MME), a configuration server, and the like, through a connectionto a Dynamic Host Configuration Protocol (DHCP)/Domain Name System (DNS)server. Upon completion of this process, the eNB may create a securetunnel to be used for S1 and X2 links in preparation for communicationwith a storage server, from which the eNB can obtain a new parameterset. Neighbor relations may be optionally set through the automatedfunctions.

Automatic Neighbor Relation (ANR) aims to minimize or remove, ifpossible, the operations on neighbor information when installing a neweNB and optimizing the neighbor information. The ANR function mayprovide an automated method of acquiring and setting neighborinformation to another eNB or a neighbor cell in an eNB or a cell, towhich a User Equipment (UE) is currently connected. For the purpose ofhandover, the ANR function may automatically set an X2 interface thatsupports an interface between eNBs in Long Term Evolution (LTE).

An Evolved Universal Terrestrial Radio Access (EUTRA) Cell Global ID(ECGI), a Cell Global Identity (CGI), and a Global eNB ID (GEI) neededto set the X2 interface will be described with reference to thefollowing table.

Table 1 illustrates relationships among the ECGI, CGI, and GEI.

TABLE 1 EUTRA CELL GLOBAL ID (ECGI) PLMN ID CELL GLOBAL ID (28 bit)Mobile Mobile eNB ID (20 bit) Cell ID country code network code (8 bit)GLOBAL eNB ID PLMN ID Mobile Mobile eNB ID country code network code

The ECGI may include the CGI and the first Public Land Mobile Network ID(PLMN ID) in a Broadcast Public Land Mobile Network ID LIST (BPLMN IDLIST). The BPLMN LIST represents a list of PLMN IDs supported by thecell. Typically, the first PLMN ID may be a PLMN ID of a global eNB IDof an eNB managing the cell and the first PLMN ID may be defined as aPrimary PLMN ID. The PLMN ID may include a mobile country code and amobile network code. The CGI may include an eNB ID and a cell ID, andthe cell ID and the eNB ID included in the CGI may be 8 bits and 20 bitsin length, respectively. The GEI may include a PLMN ID and an eNB ID ofthe eNB.

For example, assuming that a first cell operates a first eNB and asecond cell operates a second eNB, there is a need for a CGI included inan ECGI of the second cell and a PLMN ID of the second eNB, in order forthe first cell to add and manage the second cell as its neighbor cell.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Recently, however, an operator sharing a cell may not broadcastinformation about a primary PLMN ID of the shared cell in order toexclusively use the allocated frequency band. In other words, the secondcell broadcasts only its own PLMN ID for an ECGI except for a PLMN IDfor a global eNB ID of the second eNB. Therefore, the first cell mayacquire only the PLMN ID for the ECGI of the second cell and the firstcell may fail a handover operation since the first cell may recognizethe PLMN ID for ECGI of the second cell as the PLMN ID for the globaleNB ID of the second eNB which is needed to achieve X2 setup. That is,the PLMN ID for the ECGI of the second cell may be mistaken for the PLMNID for the global eNB ID of the second eNB.

Accordingly, there exists a need for an improved method and apparatusfor acquiring cell identifiers (or a PLMN ID for a global eNB ID of aneNB) in a radio communication system.

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to provide a method and apparatus for acquiring cellidentifiers in a radio communication system.

Another aspect of the present disclosure is to provide a method andapparatus for acquiring cell identifiers in an environment wheremultiple operators share cells, in a radio communication system.

Another aspect of the present disclosure is to provide a method andapparatus for registering neighbor relationships by acquiring cellidentifiers in an environment where multiple operators share cells, in aradio communication system.

In accordance with an aspect of the present disclosure, a method foracquiring a cell identifier by a source cell in a radio communicationsystem is provided. The method includes receiving information about anew cell from a User Equipment (UE) in the source cell, acquiring anEvolved Universal Terrestrial Radio Access (EUTRA) Cell GlobalIdentifier (ECGI) of the new cell from the UE, if it is determined basedon the information about the new cell that there is no neighborrelationship with the new cell, determining whether a Public Land MobileNetwork (PLMN) Identifier (ID) (PLMN ID) in the ECGI is included in amapping table between a primary PLMN ID and a shared PLMN ID, andacquiring an X2 Internet Protocol (IP) address of the new cell from anEvolved Packet Core (EPC) according to the determination results.

In accordance with another aspect of the present disclosure, a methodfor supporting a source cell to acquire a cell identifier by a UE in aradio communication system is provided. The method includes detecting anew cell, and reporting information about the new cell to the sourcecell to allow the source cell to acquire a cell identifier.

In accordance with still another aspect of the present disclosure, amethod for supporting a source cell to acquire a cell identifier by anEPC in a radio communication system is provided. The method includesdetermining whether a PLMN ID in an ECGI of a new cell different fromthe source cell is included in a mapping table between a primary PLMN IDand a shared PLMN ID, and providing an X2 IP address of the new cell tothe source cell according to the determination results.

In accordance with yet another aspect of the present disclosure, asource cell in a radio communication system is provided. The source cellincludes a receiving unit configured to receive information about a newcell from a UE in the source cell, a control unit configured to acquirean ECGI of the new cell from the UE, if it is determined based on theinformation about the new cell that there is no neighbor relationshipwith the new cell, determine whether a PLMN ID in the ECGI is includedin a mapping table between a primary PLMN ID and a shared PLMN ID, andacquire an X2 IP address of the new cell from an EPC according to thedetermination results.

In accordance with still another aspect of the present disclosure, a UEthat supports a source cell to acquire a cell identifier in a radiocommunication system is provided. The UE includes a control unitconfigured to detect a new cell, and report information about the newcell to the source cell to allow the source cell to acquire a cellidentifier.

In accordance with still another aspect of the present disclosure, anEPC that supports a source cell to acquire a cell identifier in a radiocommunication system is provided. The EPC includes a control unitconfigured to determine whether a PLMN ID in an ECGI of a new celldifferent from the source cell is included in a mapping table between aprimary PLMN ID and a shared PLMN ID, and to provide an X2 IP address ofthe new cell to the source cell according to the determination results.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates relationships among an Evolved Universal TerrestrialRadio Access (EUTRA) Cell Global Identifier (ECGI), a Cell GlobalIdentity (CGI) and a Global eNB ID (GEI) according to a first embodimentof the present disclosure;

FIG. 2 illustrates an operation process of a system according to thefirst embodiment of the present disclosure;

FIG. 3 illustrates relationships among an ECGI, a CGI and a GEIaccording to a second embodiment of the present disclosure; and

FIG. 4 illustrates an operation process of a system according to thesecond embodiment of the present disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skilled in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

In this disclosure, it will be assumed that a cell can be managed tohave a different PLMN ID for an ECGI from a PLMN ID for a global eNB ID.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to those ofskill in the art, may occur in amounts that do not preclude the effectthe characteristic was intended to provide.

The present disclosure provides a method and apparatus for acquiringcell identifiers in a radio communication system.

In addition, the present disclosure provides a method and apparatus foracquiring cell identifiers in an environment where multiple operatorsshare cells, in a radio communication system.

Moreover, the present disclosure provides a method and apparatus forregistering neighbor relationships by acquiring cell identifiers in anenvironment where multiple operators share cells, in a radiocommunication system.

Although the cell identifier acquisition method and apparatus proposedin the present disclosure will be applied to a Long Term EvolutionAdvanced (LTE-A) mobile communication system in the followingdescription, it is to be understood that this is merely by way ofexample and that the proposed cell identifier acquisition method andapparatus may be used not only in the LTE-A mobile communication system,but also in other cellular radio communication systems such as a HighSpeed Downlink Packet Access (HSDPA) mobile communication system, a HighSpeed Uplink Packet Access (HSUPA) mobile communication system, a LongTerm Evolution (LTE) mobile communication system, a 3^(rd) GenerationProject Partnership 2 (3GPP2) High Rate Packet Data (HRPD) mobilecommunication system, an Institute of Electrical and ElectronicsEngineers (IEEE) 802.16m mobile communication system, and the like.

In first and second embodiments of the present disclosure, a source cellwill be referred to as a first cell, and a new cell (or target cell)will be referred to as a second cell.

It will be assumed in FIGS. 1 and 2 that first and second cells 100 and120 and first and second eNBs 110 and 130 have the same Public LandMobile Network Identifier (PLMN ID)=A, the first cell 100 has an ID=1,and the first eNB 110 has an ID=10. Therefore, a Cell Global Identity(CGI) of the first cell 100 is 10.1 that includes the first eNB's ID=10and the first cell's ID=1, and an Evolved Universal Terrestrial RadioAccess (EUTRA) Cell Global Identifier (ECGI) is A.10.1 that includes thefirst PLMN ID=A in a Broadcast Public Land Mobile Network ID LIST (BPLMNLIST) and the CGI=10.1.

In the same way, if it is assumed that an ID of the second cell 120 is 2and an ID of the second eNB 130 is 20, a CGI of the second cell 120 is20.2 that includes the second eNB's ID=20 and the second cell's ID=2,and an ECGI thereof is A.20.2 that includes the first PLMN ID (i.e., aprimary PLMN ID)=A in the BPLMN LIST, and the CGI=20.2.

In addition, a Global eNB ID (GEI) of the first eNB 110 is A.10 thatincludes the primary PLMN ID=A and the first eNB's ID=10, and a GEI ofthe second eNB 130 is A.20 that includes the primary PLMN ID=A and thesecond eNB's ID=20.

FIG. 1 illustrates relationships among an ECGI, a CGI and a GEIaccording to a first embodiment of the present disclosure.

Referring to FIG. 1, a communication system may include the first cell100, the first eNB 110, the second cell 120, the second eNB 130, aMobility Management Entity (MME) 140, and a UE existing in the firstcell 100. If the UE corresponds to the first cell 100 operated by thefirst eNB 110, the UE may newly discover the second cell 120 and acquirecell information that includes System Information (SI). Since the secondcell 120 broadcasts its own cell information to broadcast the currentlyavailable BPLMN LIST=(A,B) and a CGI that includes the second cell'sID=20 and the second eNB's ID=2, the UE, upon receiving the BPLMN LIST,may transmit the CGI=20.2 and the first PLMN ID=A to the first cell 100.Therefore, the first eNB 110 may recognize a GEI of the second eNB 130as A.20, determining that an ECGI of the second cell 120 is A.20.2(ECGI=A.20.2). Thereafter, the first eNB 110 may request X2 setup, usingthe PLMN ID=A of the second eNB 130, which is included in the recognizedGEI=A.20.

FIG. 2 illustrates an operation process of a system according to thefirst embodiment of the present disclosure.

Referring to FIG. 2, in operation 201, a terminal 250 connected to thefirst cell 100 may determine or detect the presence of the second cell120, for different cells between which an inter-eNB neighborrelationship is not set.

The second cell 120 may broadcast its own cell information that includesSI. In operation 203, the UE 250 may transmit, to the first cell 100, aPhysical Cell ID (PCI), which is received through the cell informationand represents a cell identifier in a physical layer.

In operation 205, the first cell 100 may send, to the UE 250, an SIrequest for acquiring an ECGI of the second cell 120 to additionallymanage the second cell 120 as its neighbor cell, determining that a PCIfor the second cell 120 is not present in a database managed by thefirst cell 100.

In operation 207, the UE 250 may receive a CGI that includes a secondeNB's ID and a second cell's ID, and a BPLMN LIST supported by thesecond cell 120, by analyzing the cell information broadcasted by thesecond cell 120.

In operation 209, the UE 250 may transmit, to the first cell 100, theCGI that includes the second eNB's ID and the second cell's ID, and theECGI that includes a PLMN ID supporting the second cell 120.

In operation 211, the first cell 100 may attempt to acquire an X2 IPaddress by transmitting, to an Evolved Packet Core (EPC) 260, a GEI thatincludes the second eNB's ID and a primary PLMN ID, which are acquiredin operation 209. The process of attempting to acquire an IP address mayuse setup transfer (or S1AP ENB CONFIGURATION TRANSFER).

In operation 213, the EPC 260 may transmit the relevant IP addressacquisition information to the second eNB 130 using the received GEI.

In operation 215, the second eNB 130 may transmit an IP address for itsX2 to the EPC 260, if the second eNB 130 supports the first cell 100. Inthis case, S1AP ENB CONFIGURATION TRANSFER and MME CONFIGURATIONTRANSFER may be used.

In operation 217, the first cell 100 may acquire an IP of the second eNB130 operating the second cell 120, through the EPC 260. In operation219, the first cell 100 may request X2 setup using the acquired X2 IPaddress of the second eNB 130. In operation 221, the first cell 100 maycomplete its operation if the second cell 120 responds to the request.

Referring to FIGS. 3 and 4, a second embodiment is described. In thesecond embodiment, it will be assumed that a PLMN ID for a global eNB IDof a second eNB 330 is different from a PLMN ID for an ECGI of a secondcell 320 in the network, and as to its broadcast cell information, thesecond cell 320 broadcasts only its (i.e., the second cell's) own PLMNID for the ECGI.

It will be assumed in FIGS. 3 and 4 that a first cell 300 has an ID=1, afirst eNB 310 has an ID=10, and the first cell 300 and the first eNB 310have a PLMN ID for an ECGI=A. Therefore, a CGI is 10.1 that includes anID=10 of the first eNB 310 and an ID=1 of the first cell 300; a GEI isA.10 that includes an ID=10 of the first eNB 310 and a PLMN ID for aglobal eNB ID=A of the first eNB 310; and an ECGI is A.10.1 thatincludes a PLMN ID for the ECGI=A of the first cell 300 and theCGI=10.1.

In the same way, it will be assumed that the second cell 320 has anID=2, the second eNB 330 has an ID=20, the second cell 320 has a PLMN IDfor an ECGI=B, and the second eNB 330 has a PLMN ID for a global eNBID=A. Therefore, a CGI is 20.2 that includes an ID=20 of the second eNB330 and an ID=2 of the second cell 320; a GEI is A.20 that includes anID=20 of the second eNB 330 and a PLMN ID for the global eNB ID=A of thesecond eNB 330, and an ECGI is B.20.2 that includes a PLMN ID for theECGI=B of the second cell 320 and the CGI=20.2.

In addition, it will be assumed that a third eNB 340 has an ID=20 and aGEI=B 0.20.

FIG. 3 illustrates relationships among an ECGI, a CGI and a GEIaccording to a second embodiment of the present disclosure.

Referring to FIG. 3, the system may include the first cell 300, thefirst eNB 310, the second cell 320, the second eNB 330, the third eNB340, an MME 350, and a UE existing in the first cell 300.

For example, a process of performing X2 setup by the first cell 300 andthe second cell 320 will be described below.

If the UE corresponds to the first cell 300 of the first eNB 310, the UEmay newly discover the second cell 320 and perform SI request.Thereafter, upon receiving a BPLMN ID LIST=B that the second cell 320 iscurrently broadcasting, the UE may transmit a CGI=20.2 and a PLMN ID=Bto the first eNB 310. In this case, the first eNB 310 may recognize evena GEI of the second eNB 330 as B.20, determining that an ECGI of thesecond cell 320 is B.20.2. As a result, the first eNB 310 may send an X2setup request not to the second eNB 330, but to the third eNB 340. TheX2 setup request may include a process in which the first cell 300acquires an X2 IP address of the second cell 320.

Therefore, the first cell 300 may use a mapping table as defined inTable 2. The mapping table may represent mapping relationships between aprimary PLMN (or a primary PLMN for Global eNB ID) and a shared PLMN (ora shared PLMN ID for EUTRA CGI).

TABLE 2 Primary PLMN ID for Shared PLMN ID for Global eNB ID EUTRA CGI AB C

When using the mapping table, the first cell 300 may determine whetherthe PLMN ID in the ECGI is included in the mapping table between theprimary PLMN and the shared PLMN, and map the PLMN IDs depending on thedetermination results. Since the second cell 320 broadcasts only thecurrently available BPLMN ID LIST=B, the first eNB 310 may recognize aGEI of the second eNB 330 as A.20 by mapping the PLMN ID=B of the secondcell 320 to A. Thereafter, based on the GEI, the first eNB 310 mayrecognize the second eNB 330 and request X2 setup. If a PLMN ID for aglobal eNB ID of a neighbor eNB does not coincide with a PLMN ID for anECGI of the neighbor eNB's cell, the first eNB 310 may map PLMN IDs forglobal eNB IDs of the neighbor eNB and the cells corresponding to theneighbor eNB using the mapping table, thereby preventing errors fromoccurring in X2 setup.

The X2 setup request corresponds to a process in which a source cellacquires an X2 IP address of a new cell. The process of acquiring an X2IP address will be described with reference to an operation process ofFIG. 4 according to the second embodiment of the present disclosure.

FIG. 4 illustrates an operation process according to the secondembodiment of the present disclosure.

Referring to FIG. 4, in operation 401, a terminal 250 connected to thefirst cell 300 may determine or detect the presence of the second cell320, for different eNBs between which an inter-eNB neighbor relationshipis not set.

The second cell 320 may broadcast information about its cell. Inoperation 403, the UE 250 may transmit, to the first cell 300, a PCIthat the UE 250 has received based on the information. In other words,the UE 250 may provide information about a new cell to a source cell sothat the source cell may acquire an identifier of the new cell. Theinformation about a cell may include the cell's PCI and the systeminformation.

Thereafter, in operation 405, determining that a PCI for the second cell320 is not present in a database managed by the first cell 300, thefirst cell 300 may transmit, to the UE 250, a cell information requestfor acquiring an ECGI of the second cell 320 in order to additionallymanage the second cell 320 as a neighbor cell.

In operation 407, the UE 250 may receive a CGI and a BPLMN ID LISTsupporting the second cell 320 by analyzing cell information that isbroadcasted by the second cell 320. In operation 409, the UE 250 maytransmit, to the first cell 300, an ECGI that includes the CGI and thePLMN ID=B supporting the second cell 320.

In operation 411, the first cell 300 may determine whether the PLMN ID=Bin the received ECGI is present in the mapping table. The mapping tablemay represent mapping relationships between a primary PLMN ID and a PLMNID for shared cells in the eNB.

In operation 413-1, if the PLMN ID in the ECGI received at the firstcell 300 is included in the PLMN LIST for shared cells, which isincluded in the mapping table, the first cell 300 may acquire a GEI bymapping the PLMN ID to the primary PLMN ID in the mapping table. Inother words, the source cell may acquire a GEI of a new cell by changingthe PLMN ID in the ECGI to a primary PLMN ID in the mapping table.

However, if the PLMN ID in the received ECGI is not included in the PLMNLIST for shared cells, which is included in the mapping table, the firstcell 300 may determine in operation 413-2 whether the PLMN ID is presentin the primary PLMN ID in the mapping table, and acquire a GEI bymapping the PLMN ID to the primary PLMN ID, if the PLMN ID is present inthe primary PLMN ID in the mapping table. In other words, a source cellmay determine whether the PLMN ID in the ECGI is included in the primaryPLMN LIST in the mapping table, and acquire a GEI of a new cell usingthe PLMN ID in the ECGI, if it is determined that the PLMN ID in theECGI is included in the primary PLMN LIST in the mapping table.

In operation 413-3, if the PLMN ID in the received ECGI is mapped to noitem in the mapping table, the first cell 300 may terminate the ANRfunction, disregarding the ECGI. In other words, if the PLMN ID in theECGI is not included in the mapping table, the source cell may terminatethe ANR function, discarding information about the new cell.

In operation 415, the first eNB 310 may attempt to acquire an X2 IPaddress to the EPC using the GEI that is acquired in operation 413-1 or413-2. Operation 415 may use S1AP ENB CONFIGURATION TRANSFER. Inoperation 417, the EPC may transmit IP address acquisition informationfor the second cell 320 to the second eNB 330 using the received GEI. Inoperation 419, the second eNB 330 may transmit, to the EPC, an X2 IPaddress for the second eNB 330, if the second eNB 330 supports the firstcell. In operation 421, the EPC may transmit an X2 IP address of thesecond eNB 330 managing the second cell 320, to the first eNB 310. Inoperation 423, the first eNB 310 may request X2 setup using the acquiredX2 IP address of the second eNB 330. In operation 425, the first eNB 310may end the operation if the second eNB 330 responds to the request.

In other words, the EPC may provide the X2 IP address of a new cell to asource cell depending on whether a PLMN ID in an ECGI of the new celldifferent from the source cell is included in the mapping table betweenthe primary PLMN and the shared PLMN.

Although not illustrated in the drawings, the source cell may include areceiving unit, a transmitting unit, a control unit, and a storage unit.The control unit may control the overall operation of the source cell,and the receiving unit may receive various messages from a UE, a newcell and an EPC. The transmitting unit may send various messages to theUE, the new cell and the EPC, and the storage unit may store variousmessages received by the receiving unit, and various programs needed tooperate the source cell. For the source cell, the receiving unit, thetransmitting unit, the control unit and the storage unit may beseparately implemented, or the receiving unit, the transmitting unit,the control unit and the storage unit may be implemented in a singlecombined unit.

In addition, although not illustrated in the drawings, the new cell mayinclude a receiving unit, a transmitting unit, a control unit, and astorage unit. The control unit may control the overall operation of thenew cell, and the receiving unit may receive various messages from a UE,a source cell and an EPC. The transmitting unit may send variousmessages to the UE, the source cell and the EPC, and the storage unitmay store various messages received by the receiving unit, and variousprograms needed to operate the new cell. For the new cell, the receivingunit, the transmitting unit, the control unit and the storage unit maybe separately implemented, or the receiving unit, the transmitting unit,the control unit and the storage unit may be implemented in a singlecombined unit.

Further, although not illustrated in the drawings, the EPC may include areceiving unit, a transmitting unit, a control unit, and a storage unit.The control unit may control the overall operation of the EPC, and thereceiving unit may receive various messages from a source cell and a newcell. The transmitting unit may send various messages to the source celland the new cell, and the storage unit may store various messagesreceived by the receiving unit, and various programs needed to operatethe EPC. For the EPC, the receiving unit, the transmitting unit, thecontrol unit and the storage unit may be separately implemented, or thereceiving unit, the transmitting unit, the control unit and the storageunit may be implemented in a single combined unit.

Moreover, although not illustrated in the drawings, the UE may include areceiving unit, a transmitting unit, a control unit, and a storage unit.The control unit may control the overall operation of the UE, and thereceiving unit may receive various messages from a source cell and a newcell. The transmitting unit may send various messages to the source celland the new cell, and the storage unit may store various messagesreceived by the receiving unit, and various programs needed to operatethe UE. For the UE, the receiving unit, the transmitting unit, thecontrol unit and the storage unit may be separately implemented, or thereceiving unit, the transmitting unit, the control unit and the storageunit may be implemented in a single combined unit.

As is apparent from the foregoing description, the present disclosuremay provide a method and apparatus for eliminating the restrictions thata PLMN ID of an eNB should be used as a PLMN ID of a cell duringhandover, thereby addressing ANR malfunctions which may occur when it isoperated to block the unnecessary system information.

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method for acquiring a cell identifier by asource cell in a radio communication system, the method comprising:receiving information about a new cell from a user equipment (UE) in thesource cell; acquiring an evolved universal terrestrial radio access(EUTRA) cell global identifier (ECGI) of the new cell from the UE, if itis determined based on the information about the new cell that there isno neighbor relationship with the new cell; determining whether a publicland mobile network (PLMN) identifier (ID) (PLMN ID) in the ECGI isincluded in a mapping table between a primary PLMN ID and a shared PLMNID; acquiring an X2 internet protocol (IP) address of the new cell froman evolved packet core (EPC) according to the determination results; anddiscarding the information about the new cell if the PLMN ID in the ECGIis not included in the mapping table.
 2. The method of claim 1, whereinthe acquiring of the X2 IP address of the new cell from the EPCcomprises: if the PLMN ID in the ECGI is included in a shared PLMN IDlist included in the mapping table, acquiring a global enhanced Node B(eNB) ID of the new cell by using a primary PLMN ID which is included inthe mapping table and corresponds to the PLMN ID in the ECGI.
 3. Themethod of claim 1, wherein the acquiring of the X2 IP address of the newcell from the EPC comprises: determining whether the PLMN ID in the ECGIis included in a primary PLMN ID list in the mapping table, if the PLMNID in the ECGI is not included in the shared PLMN ID list included inthe mapping table; and acquiring a global enhanced Node B (eNB) ID ofthe new cell using the PLMN ID in the ECGI, if it is determined that thePLMN ID in the ECGI is included in the primary PLMN ID list in themapping table.
 4. The method of claim 1, wherein the information aboutthe new cell includes a physical cell identifier (PCI) of the new celland system information (SI) of the new cell.
 5. A method for supportinga source cell to acquire a cell identifier by an evolved packet core(EPC) in a radio communication system, the method comprising:determining whether a public land mobile network (PLMN) identifier (ID)(PLMN ID) in an evolved universal terrestrial radio access (EUTRA) cellglobal identifier (ECGI) of a new cell different from the source cell isincluded in a mapping table between a primary PLMN ID and a shared PLMNID; and providing an X2 internet protocol (IP) address of the new cellto the source cell according to the determination results; and stoppingproviding the X2 IP address of the new cell, if the PLMN ID in the ECGIis not included in the mapping table.
 6. The method of claim 5, whereinthe providing of the X2 IP address of the new cell to the source cellcomprises: if the PLMN ID in the ECGI is included in a shared PLMN IDlist included in the mapping table between the primary PLMN ID and theshared PLMN ID, providing a global enhanced Node B (eNB) ID of the newcell by using the primary PLMN ID which is included in the mapping tableand corresponds to the PLMN ID in the ECGI.
 7. The method of claim 5,wherein the providing of the X2 IP address of the new cell to the sourcecell comprises: providing a global enhanced Node B (eNB) ID of the newcell using the PLMN ID in the ECGI, if the PLMN ID in the ECGI is notincluded in a shared PLMN ID list included in the mapping table and thePLMN ID in the ECGI is included in a primary PLMN ID list in the mappingtable.
 8. The method of claim 5, wherein information about the new cellincludes a physical cell identifier (PCI) of the new cell and systeminformation (SI) of the new cell.
 9. A source cell apparatus in a radiocommunication system, the apparatus comprising: a receiving unitconfigured to receive information about a new cell from a user equipment(UE) in the source cell; and a control unit configured to: acquire anevolved universal terrestrial radio access (EUTRA) cell globalidentifier (ECGI) of the new cell from the UE, if it is determined basedon the information about the new cell that there is no neighborrelationship with the new cell; determine whether a public land mobilenetwork (PLMN) identifier (ID) (PLMN ID) in the ECGI is included in amapping table between a primary PLMN ID and a shared PLMN ID; acquire anX2 Internet Protocol internet protocol (IP) address of the new cell froman evolved packet core (EPC) according to the determination results; anddiscard the information about the new cell, if the PLMN ID in the ECGIis not included in the mapping table.
 10. The apparatus of claim 9,wherein if the PLMN ID in the ECGI is included in a shared PLMN ID listincluded in the mapping table, the control unit acquires a globalenhanced Node B (eNB) ID of the new cell by using a primary PLMN IDwhich is included in the mapping table and corresponds to the PLMN ID inthe ECGI.
 11. The apparatus of claim 9, wherein the control unitdetermines whether the PLMN ID in the ECGI is included in a primary PLMNID list in the mapping table, if the PLMN ID in the ECGI is not includedin the shared PLMN ID list included in the mapping table, and acquires aglobal enhanced Node B (eNB) ID of the new cell using the PLMN ID in theECGI, if it is determined that the PLMN ID in the ECGI is included inthe primary PLMN ID list in the mapping table.
 12. The apparatus ofclaim 9, wherein the information about the new cell includes a physicalcell identifier (PCI) of the new cell and system information (SI) of thenew cell.
 13. An evolved packet core (EPC) that supports a source cellto acquire a cell identifier in a radio communication system, the EPCcomprising: a control unit configured to: determine whether a publicland mobile network (PLMN) identifier (ID) (PLMN ID) in an evolveduniversal terrestrial radio access (EUTRA) cell global identifier (ECGI)of a new cell different from the source cell is included in a mappingtable between a primary PLMN ID and a shared PLMN ID; provide an X2internet protocol (IP) address of the new cell to the source cellaccording to the determination results; and stop providing the X2 IPaddress of the new cell, if the PLMN ID in the ECGI is not included inthe mapping table.
 14. The EPC of claim 13, wherein if the PLMN ID inthe ECGI is included in a shared PLMN ID list included in the mappingtable between the primary PLMN ID and the shared PLMN ID, the controlunit provides a global enhanced Node B (eNB) ID of the new cell by usingthe primary PLMN ID which is included in the mapping table andcorresponds to the PLMN ID in the ECGI.
 15. The EPC of claim 13, whereinthe control unit provides a global enhanced Node B (eNB) ID of the newcell using the PLMN ID in the ECGI, if the PLMN ID in the ECGI is notincluded in a shared PLMN ID list included in the mapping table and thePLMN ID in the ECGI is included in a primary PLMN ID list in the mappingtable.
 16. The EPC of claim 13, wherein information about the new cellincludes a physical cell identifier (PCI) of the new cell and systeminformation (SI) of the new cell.